Antenna apparatus

1. An antenna apparatus comprising: a transmitting antenna and a plurality of receiving antennas, the antenna apparatus being used for an azimuth detection apparatus, in which each of the receiving antennas receives radio waves transmitted from the transmitting antenna and reflected by an object, and an azimuth of the object is detected based on a phase difference between received signals, wherein the transmitting antenna includes a plurality of transmitting-side unit antennas arranged in a predetermined arranging direction at predetermined transmitting-side arrangement intervals, the plurality of receiving antennas are arranged in the predetermined arranging direction at predetermined arrangement intervals, each of the receiving antennas includes a plurality of receiving-side unit antennas arranged in the predetermined arranging direction at predetermined receiving-side arrangement intervals, the receiving-side arrangement interval is larger than the transmitting-side arrangement interval, a width of the transmitting antenna is measured along an axis parallel with the predetermined arranging direction, the receiving-side arrangement interval is less than the width of the transmitting antenna, both the transmitting antenna and the receiving antennas are formed of strip conductors and on one surface of a dielectric substrate, a transmitting-side feeding line and a receiving-side feeding line are formed of strip conductors on the one surface so that power is fed to the transmitting antenna via the transmitting-side feeding line and to the receiving antennas via the receiving-side feeding line, each of the transmitting-side unit antennas and each of the receiving-side unit antennas is formed of a plurality of radiating elements that have a rectangular shape and are arranged in a direction orthogonal to the arranging direction, each of the radiating elements of the transmitting-side unit antennas have a first side and a second side shorter than the first side, wherein the first side extends in a first direction and the second side is opposite to the transmitting-side feeding line, each of the radiating elements of the receiving-side unit antennas has a first side and a second side shorter than the first side, wherein the first side extends in a second direction opposite to the first direction and the second side is opposite to the receiving-side feeding line, and a transmission and reception composition characteristic, which is a composition of a directivity of the transmitting antenna and a directivity of the receiving antenna, has a main lobe including at least the whole of a predetermined detection angle range, and the transmitting-side arrangement interval and the receiving-side arrangement interval are determined so that, in the whole of the detection angle range, a ratio of the intensity of the main lobe of the transmission and reception composition characteristic at a given angle in the detection angle range to the intensity of the transmission and reception composition characteristic generated as a false image at the angle by wrap around at the angle due to grating becomes equal to or more than a predetermined threshold value.

2. An antenna apparatus comprising: a transmitting antenna and a plurality of receiving antennas, the antenna apparatus being used for an azimuth detection apparatus, in which each of the receiving antennas receives radio waves transmitted from the transmitting antenna and reflected by an object, and an azimuth of the object is detected based on a phase difference between received signals; and both the transmitting antenna and the receiving antenna are formed of strip conductors and on one surface of a dielectric substrate, a transmitting-side feeding line and a receiving-side feeding line formed of strip conductors on the one surface such that power is fed to the transmitting antenna via the transmitting-side feeding line and to the receiving antennas via the receiving-side feeding line, wherein: the transmitting antenna includes a plurality of transmitting-side unit antennas arranged in a predetermined arranging direction at a predetermined transmitting-side arrangement interval, each of the transmitting-side unit antennas is formed of a plurality of transmitting radiating elements that have a rectangular shape and are arranged in a direction orthogonal to the predetermined arranging direction, wherein a first side of each of the plurality of radiating elements is directed in a first direction and a second side of each of the plurality of radiating elements is opposite to the transmitting-side feeding line, and the first side is longer than the second side, the plurality of receiving antennas are arranged in the predetermined arranging direction at a predetermined arrangement interval, each of the receiving antennas includes a plurality of receiving-side unit antennas arranged in the predetermined arranging direction at a predetermined receiving-side arrangement interval, each of the receiving-side unit antennas is formed of a plurality of receiving radiating elements that have a rectangular shape and are arranged in the direction orthogonal to the predetermined arranging direction, wherein a first side of each of the plurality of receiving radiating elements is directed in a second direction that is opposite to the first direction, a second side of each of the plurality of radiating elements is opposite to the receiving-side feeding line, and the first side is longer than the second side, a width of the transmitting antenna is measured along an axis parallel with the predetermined arranging direction, and the receiving-side arrangement interval is less than the width of the transmitting antenna and is greater than the transmitting-side arrangement interval.